20 PSI regulator for Forced Air Burner?

J

jawilder

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Jun 27, 2006
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I fired up my forced air burner last night for the first time. My air supply is the good ole hair dryer with airflow controlled by a brass gate valve. The regulator I used is set 20 PSI similar to this one
bcm5hpr1_regulator_kit.jpg


I was having problems getting the flame just right. It may need to be adjusted more between air/gas. At first it was having problems staying lit. I lowered the air flow, but still wasn't getting the jet flame I've seen others get. I don't have any kind of burner tip. It's just 1" black nipple.

Could it be that I'm running too much LP or do I need to just play with it some more?
Jason
 
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So, you have a 1" dia. burner tube. What do you have for a gas orifice on your burner? Normally 20 psi is way more than enough to run a blown burner, they run at 1-5 or so psi usually. This is because the gas jet is usually pretty large, from 1/16" up to just the end of the 1/4" delivery tube brazed in with no real orifice. If you are running 20 psi with no jet at the end of your fuel line, that would be WAY too much gas. My apologies if this elementary to you.

You could use the 20 psi reg with no drilled jet, etc., if you put a needle valve in line (kind of like a welding torch valve) to control how much fuel is getting to your burner.

Get your air going, and while pointing a plumbing torch into the door, gradually introduce gas with the needle valve- you should quickly reach a point where the mix is rich enough to stay lit. Then you can play with the flame and figure out how it likes to run.

Is it also possible that you have a wimpy hair dryer that isn't putting out a whole lot of air? Or if it's way too much air, try putting a gate valve or something in line to control the blast.

Hope any of this helps.
 
If you're regulating at the tank end of the connection, and then just letting it expand and flow through the pipe with no tip then you are wasting a lot of gas but by the time it gets out there it's under very little pressure. I could be misunderstanding what your setup is though.

you need SOMETHING giving it some velocity, but you sure don't want to run that much volume.
 
I believe fuel velocity is more of an issue with venturi burners- usually they will have a gas jet in a wire drill size 57 or higher, or a .035 tweco tip, etc., to get the gas sucking the air in with it.

I've noticed a fair amount of guys using forced air are pretty cavalier about their gas inlet size.
 
I do have a gate valve to limit the air. The needle valve is 1/4" and goes directly into a 1 1/2" tee. I can get the fire to stay lit but the flame is mostly yellow/orange. I'll post pics when I get to my pc
 
Mostly yellow/orange may indicate a fuel rich environment. I would think the needle valve would give you sufficient control to balance the flame, however. Pics will be good, I'm probably missing something in the larger picture. Maybe it's a forge design related issue or something.

Any chance you have a stronger blower around somewhere, like a shop vac maybe, that you could temporarily hook up to the burner? Most hair dryers I've seen don't put out a lot of air when compared to forge blowers.

How long is your burner tube? Where does the fuel come in? Maybe it's not mixing well.
 
A hair dryer does not usually provide enough air flow for a 1" burner. Try a blower fan, and you will see a HUGE difference. You really need 30-50 CFM or more. A large burner running at full flame can require a 100CFM blower. A mid size squirrel cage blower and a fan controller pot will make a good enough blower.
 
First off as mentioned a hair dryer is not sufficient for a blower. The blowers at the surplus center will work. I noticed one was a plastic housing so make not of it and be careful. Second I recommend you get an adjustable regulator. I achieve great control with my set-up. I can set it to hold 1400f to 2500f. I used the system on Kevin Cashen's website. Good luck and be safe.
 
delbert ealy said:
You also should not be using galvanized pipe for your forge manifold, use black pipe for the whole thing.

Del
Click to expand...

I would think that if the manifold got hot enough to release the zinc in the galvanized pipe it would be hot enough to cause the propane to ignite and blow the whole thing up? No question on the burner tube though.
 
You'll also notice that the burner runs a lot differently when installed in the forge as opposed to "bench testing." It shouldn't blow off the tip of the burner tube like that. Do you have your forge shell built? Try running it in there. (After you get a different blower.)

Forge building is fun. Sometimes when you are in the middle of it, you don't realize how much fun you're having until you look back at it later... and start scheming about building another one for a different purpose or modifying the one you have.
 
I have the 8" x 18" pipe cut but no hole cut out yet. The insulation is on its way. It should be finished soon.

I think DIY tools are very fun, which explains why most makers have several forges AND grinders they've built. I have already built a charcoal forge which works good, but I wanted the challenge and better use of LP.

Are there any brick and mortor stores that carry the fan I need or am I destined to buy online?
 
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